# Annotate leaf-list in a action statement
**URL:** https://dmap-community.ductus.global/t/annotate-leaf-list-in-a-action-statement/3502
**Category:** YANG
**Created:** [February 10, 2021, 11:19am UTC](https://dmap-community.ductus.global/t/annotate-leaf-list-in-a-action-statement/3502 "2021-02-10T11:19:05Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@linga.kartheek](https://dmap-community.ductus.global/u/linga.kartheek)
#### Post date: [February 10, 2021, 11:19am UTC](https://dmap-community.ductus.global/t/annotate-leaf-list-in-a-action-statement/3502/1 "2021-02-10T11:19:05Z")
Hi,
I need to annotate leaf-list with when/must to avoid getting a specific interface name based on below yang file:
```auto
container reset {
config false;
tailf:action counters {
tailf:actionpoint reset_action;
input {
choice target {
leaf-list interfaces {
type leafref {
path "/oc-if:interfaces/oc-if:interface/oc-if:config/oc-if:name";
}
}
leaf all {
}
}
}
}
}
```
i tried in multiple ways but failed to make it work
```auto
tailf:annotate "/rc-if:reset/rc-if:counters/rc-if:input/rc-if:target/rc-if:interfaces" {
1) when 'current() != "eth0"';
2) must "current() != 'eth0'";
3) must "deref(current())!='eth0'" {
tailf:dependency '.';
error-message "reset not allowed";
}
4) must "count(/oc-if:interfaces/oc-if:interface[oc-if:name = current()]/oc-if:config/oc-if:name = 'eth0')=1" {
error-message "reset not allowed";
}
}
```
Could you please suggest the right way to annotate so that eth0 is not allowed or does no appear in the list to reset the counters.
---
### Author:  [@mvf](https://dmap-community.ductus.global/u/mvf)
#### Post date: [February 10, 2021, 2:37pm UTC](https://dmap-community.ductus.global/t/annotate-leaf-list-in-a-action-statement/3502/2 "2021-02-10T14:37:45Z")
The reason is that `tailf:annotate` can be used only for adding `tailf:...` statements. If you want to add statements like `must` or `when`, you either need to modify the original YANG file, or use a deviation module (see the RFC 7950 and the confdc documentation). The deviation in your case may look like this:
```auto
deviation "/config:reset/config:counters/config:input/config:target/config:interfaces/config:interfaces" {
deviate add {
must ". != 'eth0'";
}
}
```
Note the duplication of `rc-if:interfaces` - this is because there is an implicit `case` statement.
---
### Author:  [@linga.kartheek](https://dmap-community.ductus.global/u/linga.kartheek)
#### Post date: [February 10, 2021, 4:29pm UTC](https://dmap-community.ductus.global/t/annotate-leaf-list-in-a-action-statement/3502/3 "2021-02-10T16:29:22Z")
Thanks @mvf. it worked. Is there any possibility to avoid eth0 appearing in the list? i tried with when but looks like when is not supported in deviations.
> error: unexpected keyword ‘when’
---
### Author:  [@mvf](https://dmap-community.ductus.global/u/mvf)
#### Post date: [February 11, 2021, 9:40am UTC](https://dmap-community.ductus.global/t/annotate-leaf-list-in-a-action-statement/3502/4 "2021-02-11T09:40:49Z")
Hm, right, `when` cannot be deviated, not sure why. But `when` would not help you here, a `when` statement referencing the current node is troublesome, to say the least (and `confdc` actually refuses that).
What do you mean by “to avoid eth0 appearing in the list”, do you refer to CLI completion? In that case you might need to implement a custom completion callback.
---
### Author:  [@linga.kartheek](https://dmap-community.ductus.global/u/linga.kartheek)
#### Post date: [February 11, 2021, 9:50am UTC](https://dmap-community.ductus.global/t/annotate-leaf-list-in-a-action-statement/3502/5 "2021-02-11T09:50:22Z")
Ok. Thank you.
One last question.
is it possible to put tailf:cli-completion-actionpoint or tailf:validate as part of some condition in annotate statement? validation or completion should be called only when condition is true.
example:
tailf:annotate “/oc-if:interfaces/oc-if:interface/oc-eth:ethernet/oc-eth:config/oc-eth:port-speed” {
tailf:cli-completion-actionpoint or tailf:validate when /oc-if:interfaces/oc-if:interface/oc-if:config/oc-if:name is “etho”
}
---
### Author:  [@mvf](https://dmap-community.ductus.global/u/mvf)
#### Post date: [February 11, 2021, 10:22am UTC](https://dmap-community.ductus.global/t/annotate-leaf-list-in-a-action-statement/3502/6 "2021-02-11T10:22:37Z")
No, I’m afraid nothing like that is possible, you would have to implement the condition in the callback code.
---
### Author:  [@cohult](https://dmap-community.ductus.global/u/cohult)
#### Post date: [February 11, 2021, 11:15am UTC](https://dmap-community.ductus.global/t/annotate-leaf-list-in-a-action-statement/3502/7 "2021-02-11T11:15:52Z")
Note that you can use tailf:annotate-module/statement to to annotate an existing statement with ‘must’, ‘min-elements’, ‘max-elements’, ‘mandatory’, ‘unique’, and ‘when’ statements.
---
### Author:  [@linga.kartheek](https://dmap-community.ductus.global/u/linga.kartheek)
#### Post date: [February 11, 2021, 12:51pm UTC](https://dmap-community.ductus.global/t/annotate-leaf-list-in-a-action-statement/3502/8 "2021-02-11T12:51:57Z")
Hi @cohult,
Is it possible to add a condition using annotate-statement in this case?
tailf:annotate “/oc-if:interfaces/oc-if:interface/oc-eth:ethernet/oc-eth:config/oc-eth:port-speed” {
tailf:cli-completion-actionpoint port\_speed;
}
ethernet is an augmented container in interfaces module. Also at the end i need to refer interface name to restrict to a specific port speed list. Is /oc-if:interfaces/oc-if:interface/oc-if:config/oc-if:name path accessible here?
I gave a try by using annotate-statement but couldn’t succeed.
Thanks,
Karthik